Defeating Promethean Knights:

When there are multiple Promethean Knights in an area they can be very troublesome (especially under the Legendary difficulty). To easily dispose of the knights, make sure you have a mid range weapon (pistol, DMR, battle rifle, carbine, light rifle, etc...) and the shotgun (or equivalent). Start by using your mid range weapon to head shot one of the knights from a distance, but use a low rate of fire to conserve ammo. Fire only one shot every couple of seconds. This will tick off the knight and "bait" him into doing the teleporting-dash across the map to melee you, thus bringing him in close and separating him from the rest of the knights. When you see the knight begin to teleport-dash towards you, quickly run backwards and slightly to the side to dodge his melee attack, then switch to your shotgun and blast him at point blank range. Repeat this tactic as necessary.